Grinding wheel truing apparatus



Nov. 17, 1953 o. E. HILL 2,659,359

GRINDING WHEEL TRUING APPARATUS Filed May 15 1951 4 Sheets-Sheet l g '6 171081060) a H OIVA E. HILL flatowze y Nov. 17, 1953 o. E. HILL 2,659,359

GRINDING WHEEL TRUING APPARATUS Filed May 15, 1951 4 Sheets-Sheet 2 HILL I114! Ti L- 3045 Im/eqtor OIVA E.

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fltaornez/ Nov. 17, 1953 o. E. HILL 2,659,359

GRINDING WEEL TRUING APPARATUS Filed May 15, 1951 4 Sheets-Sheet 3 F tz/eater '47 'OIVA. E. HILL I52 I33 g m uwfiiam Attorney Nov. 17, 1953 o. E. HILL 2,659,359

GRINDING WHEEL TRUING APPARATUS Filed May 15, 1951 4 Sheets-Sheet 4 fly.

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'fletamey Patented Nov. 17, 1953 2,159,359 GRINDING WHEEL TRUING APPARATUS Oiva E. Hill, West Boylston, Mass assignor to Nortoncompan'y, Worcester, Mass., a corporation ofMassaclrusetts Application May. 15, 1951, Serial No. 226,453, 4. Claims. (0]. 125-11) Theinvention relates to a. rinding wheel truingv apparatus and moreparticulariy to a truing p ra us for t ins a p edete n d ha on he r e y f agrindinewh cL T cp s n invention relates to a modified form of the truing apparatus disclosed in my copendingapplication, Serial No. 183,775, filed September 8, 1950.

One object of the invention isto provide a simple and thorou ly pr c l truin a par t s for truingan irregular surfaceon the periphery of a grinding wheel. Another object is to provide a truing apparatus for truing not only the peripheral surface of a grinding wheel but also the adjacent side faces thereof. Another object of the inventionis to true theperipheral and side faces of a grindingwheel together with afillet on one Or both corners of. th rindin whee An ther object is to provide. an hydraulically-actuated electrically-controlled. truing apparatus successively to, true the side facesand peripheral surface of a grinding wheel. Another object. of the invention is to provide a truing apparatus with a hydraulically-actuated cam mechanism auto: matically to true a sideface of the grind ng Wheel,

generate a radius and then true, the peripheral surface thereof after. which a secondradius is. trued on the opposite corner of the grinding wheel and the side face adjacent thereto istrued in a single pass of the truing tool holder. Other objects will be in part. obvious or. in part pointed out. hereinafter.

Theinvention accordingly consists in the features of construction, and arrangements of parts aswill be exemplified in the structure to behereinafter described, andthe scopeoi the application of which will be indicated in the following claims.

In the accompanying drawings, in which is shown one of. various possible, embodiments of the mechanical features of, this. invention,

Fig. 1 is av front elevation of the improved grinding wheel truing apparatus;

Fig. 2 is a plan view of the truingapparatus;

Fig. 3. is a vertical sectional view, taken approximatelyon. the line 3.3. of Fig. 1, through the truing apparatus;

Fig. 4 is a horizontal sectional view taken approximately on the line 44 of Fig. 1;

Fig. 5 is a combined hydraulic and electrical diagram of-the control and actuating mechanism for 'the truing apparatus;

' Fig. 6- is a fragmentary diagrammatic view showing the positions of the parts as the truing tool traverses towardth'e right;

Fig. '7-is a similar fragmentary diagrammatic view showing the positions of the parts after a further. traversing movement of thetruin tool toward the right; and i Fig. 8 is a fragmentary detail view of a modified truing tool holder and a. gauge to facilitate precise adjustment of the truing tools.

A truing apparatus has been illustratedinrthe drawings as applied to a grinding machinel'iaw ing a rotatable grinding wheel I .0 which is par-v tially surrounded by a wheel guard ll. The

grinding wheel [0, as illustrated, is a singlegrind ing wheel having opposed side faces and a periph eral surface together with two adjoining radii to be trued. The wheel guard serves as a support for an upwardly extending bracket I2. The bracket I 2 supports a slide base [3. The slide. base I3 is preferablysupported on 'the'bracket I 2 by means of a stand I 4in order to facilitate a swivelling movement thereof. The slide base [3 is provided'with a rearwardly. projecting lug. l5 which is arranged. between a pair of. lugs. l6 and 11 formed integrally with the bracket [2, A pair of opposed adjusting screws] 8 and 'I 9 are provided in the lugslii'and ll'respectively. The. adjusting screws. l 8 and. 19 are arranged on oppo site sides of the lug l5. It will. be readily .apparent. from the foregoing disclosure that by manipulation ofthe screws l8 and [9, the slide base l3. may be angularly adjustedon the pivot. stud l4 relative to theslide l2 tofacilitate 1ining up the slide supported thereby. A plurality of clamping screws 20, 2| and 22 are. provided to. facilitate clamping the slidebase I3 in adjusted position to the bracket l2. Thereare four clamp,- ing screws (only three of which appear in the drawings). The screws 20, 2| 7 and 22 pass, through elongated arcuate slots (not shown) formed in the bracket I 2 and are screw threaded into the slidebase l3.

The slide base I3 is provided with a dovetailed slideway 25 which mates with a correspondingly shaped dovetailed slideway fromed on. a longitudinally movable slide 26; The. slide. 26 is arranged to traverse longitudinally in a direction substantially parallel to theaxis of rotation of the grinding wheel ID.

A hydraulically operated mechanism is provided for traversing the slide 26. longitudinally comprising a hydraulic cylinder 21 which. is formed integral with the slide base l3. The cylinder 2-1. contains a slidably mounted piston 28 mounted on one end of a piston rod 29. The

other end of the piston rod 29 is fastened to a,

bracket 30 which is formedintegral with the longitudinally movable slide 26. When fluid under pressureis passed through a pipe 3 I. into a cylinder chamber 32 (Fig. 5), the piston 28 together with the slide 26 will be moved longitudinally to ward the right. During this movement of the piston 28, fluid within a cylinder chamber 33 may exhaust through a. pipe 34. A suitable fluid pressure system and a control mechanism therefor for supplying fluid under pressure to the cylinder 21 will be hereinafter described.

The longitudinally movable slide 26 serves as a support for a transversely movable vertically arranged sleeve 35. The sleeve 35 is square in cross-section as indicated in Fig. 4. The sleeve 36 is provided with a central aperture for supporting a vertically movable truing tool spindle 36. The spindle 36 supports a truing tool holder 31 at its lower end. The truing tool holder 31 supports a plurality of adjustably mounted diamonds or truing tools 38, 38a and 381), which will be more fully described hereinafter.

The sleeve 35 is provided with a pair of vertically extending ribs or guides 48 and 4| (Fig. 4) for controlling the vertical movement of the sleeve. A plurality of rollers 42, 43, 44 and 45 (Fig. 4) are mounted on studs 46, 41, 48 and 49 respectively carried by the longitudinally movable slide 26. The rollers 42, 43, 44 and 45 are arranged to engage opposite faces of the guides and 4| to support the sleeve 35 for a free vertical sliding movement relative to the longitudinally movable slide 26. The studs 48 and 49 are preferably provided with eccentric portions for supporting the rollers 44 and respectively to facilitate a transverse adjustment of the rollers so as to take up lost motion between the sliding parts. A similar set of rollers (not shown) are provided for supporting and guiding the lower ends of the guides 40 and 4|.

Similarly a plurality of rollers 50, 5|, 52 and 53 are provided for engaging the opposed faces of the guides 40 and 4|. These rollers are rotatably supported on studs 54, 55, 56 and 51 respectively. The studs and 51 are preferably provided with eccentric portions for supporting the rollers 5| and 53 respectively to facilitate a transverse adjustment of the rollers to take up backlash between the sliding parts. It will thus be seen that an anti-friction sliding support has been provided for the sleeve 35 so that it may be freely moved in a vertical direction transverse to the longitudinally movable slide 26 to carry the truing tools 38, 38a and 38b in the desired and predetermined path to true a predetermined shape on the periphery of the grinding wheel II).

A suitable adjusting mechanism is provided for adjusting the spindle 36 relative to the sleeve 35 to facilitate either a manual adjustment of the truing tools or diamonds 38 or an automatic feeding movement thereof at the ends of each reciprocably stroke of the longitudinally movable slide 26. The upper end of the sleeve 35 is provided with a fixedly mounted flange 68 which serves as a support for a bracket 6|. The upper end of the spindle 36 is provided with a screw thread 63 which surrounds with and meshes with a rotatable nut 64. The rotatable nut 64 is rotatably supported on the flanged portion of the sleeve 35. A gear 65 is keyed to the nut 64 and meshes with a pinion 66. The pinion 66 is mounted on the upper end of a vertically arranged rotatable shaft 61. The shaft 61 is rotatably mounted within the bracket 6| and is provided at its lower end with a manually operable hand wheel 68. It will be readily apparent from the foregoing disclosure that rotation of the hand wheel 68 will be transmitted through the shaft 61, the pinion 66, the gear 65 to rotate the nut 64 and thereby impart a vertical axial adjustment to the truing tool spindle 36 relative to the sleeve 35.

In order to hold the nut 64 in adjusted position, a serrated wheel 69 is fixedly mounted on the upper end of the shaft 61. A spring pressed pawl 10 mounted on the bracket 6| is arranged to engage the periphery of the serrated wheel 68 and thereby to hold the feed nut 64 in adjusted position.

In order to steady the upwardly extending portion of the feed screw 63 and to hold it against rotation, an arm 1| is clamped around a cylindrical portion 12 formed on the upper end of the screw 63 (Figs. 1 and 2). The right-hand end of the arm 1| (Fig. 1) is provided with a spring pressed ball 13 which rides in a vertically arranged groove 14 formed in a vertically extending bracket 15. The bracket 15 is fixedly mounted on the flanged portion 68 of the sleeve 35. It will be readily apparent from the foregoing disclosure that the arm 1| serves to hold the screw 63 and the spindle 36 against rotary motion but allows free axial movement thereof.

It is desirable to provide an automatically actuated mechanism for imparting a feeding movement to the truing tools 38 at the ends of the longitudinal traversing movement thereof. This is preferably accomplished by means of a pawl and ratchet mechanism comprising a ratchet wheel 16 which is keyed to the nut 64. A pawl carrier 11 is rotatably mounted on the nut 64 and is provided with a pivotally mounted feed pawl 18. The feed pawl 18 is supported by a stud 19 fastened to the pawl carrier 11. A compression spring 88 serves normally to maintain the pawl 18 in operative engagement with the ratchet wheel 16. A manually operable rotatable eccentric 8| is provided to facilitate rocking the pawl 18 to an inoperative position if desired so as to facilitate a manual adjustment of the truing tool spindle 36. A compression spring 82 (Figs. 1 and 2) normally urges the pawl carrier 11 in a clockwise direction (Fig. 2) with a stud 83 in operative engagement with a stop surface 84 which is fixedly mounted on the flange 68 of the sleeve 35.

An automatically operated mechanism is provided for actuating the pawl carrier 11 at the ends of the longitudinal traversing movement of the truing tool to facilitate automatically feeding the truing tools 38, 38a and 38b downwardly before each longitudinal pass of the truing tool across the peripheral face of the grinding wheel Hi. When the slide 26 approaches the righthand end of its stroke, the pawl carrier 11 engages an adjustable dog 85 which serves to rock the pawl carrier 11 in a counter-clockwise direction during continued movement of the slide 26 toward the right so as to impart a predetermined down feeding movement to the truing tools 38. The adjustable dog 85 is adjustably supported by a T-slot 86 formed in the upper surface of the bracket l2. The dog 85 extends vertically a suflicient distance to allow maximum vertical movement of the spindle 36 and the sleeve 35.

The pawl carrier 11 is provided with a laterally extending arm 81 which supports a stud 68. A roller 89 is mounted on the stud 88. The roller 88 is arranged in the path of a cam face 90 formed on an adjustable dog 8| so that when the longitudinally movable slide approaches the lefthand end of its stroke, the pawl carrier 11 is rocked in a counter-clockwise direction so as to impart a predetermined, downgfeeding movement feeding motion imparted to the truing tools; It

will be readily: apparent i from; the ;-foregoing dis: closure that whenztheslide .126 traverses; toward.

the right, the-pawl'carrier 'IItwill move into en.-.

gagement with the dog- 85.-'as the. slide 26 ap; proaches. the right-hand aend ofits, stroke there--.. by imparting. a down :feeding movement. to the, truing-tools 38 beforethe return stroke. ofthe:

slide 26. Similarly when the slide 2 6;.travels to-,

ward'the left,- the. roller 89::will engage the. cam. as the slide 26" approaches. thevleft-hand end :of, its stroke -,to impart-a down;

face 90 onthe dog 9 I feedingmovement to the truing tool 38.

A suitable formingmechanism is providedfor generating a predetermined shape-on-the pee riphery of the grindingwheel III. This shape.- may. for example comprise. truing: the two..side:.faces.; of the grinding wheel, the periphery-thereof and fillets between the side faces and the periphery. This mechanism may comprise a forming: bar. 95

which is anchored to =a bracket=96 by means ofaa.

clamping bolt 9-1. Anadjustingscrew 98:serves. to

precisely adjust'theforming bar 95 in ailongitu-fl dinal 'directionrelative to the bracket-96-to facil+ itatesetting up themechanism. The bracket: 9d; is-flxedl'y supported onthe fixed bracket l2. The

forming bar'95 extends through an elongated'slot formed in the sliden endthe-sleeve 35and isarranged to-slide upona slidesurface" I formed 1 on the longitudinally movable: slide 26. An arrow-pointed follower I III isflxedly mounted 1 on the sleeve 35 i and isarrangedto follow a portion-0f the form on-theiormbar 95 'duringthelongitudinal movementot. the slide-26 m a man ner to be-hereinafter described.- The follower I l'II is-shaped with a-pluralityof apexes IOIa, IIlIb, and IflIe;

Th'ediamonds or truing tools 38; wand-38b may beprecisely positioned'and generatedtocorrespond with the-shape of the apexes I 0 I a; I0 I h and I 0Ie-of thefollower I III or if desired the; truing -tools 38', 38a and 38b may beadjustablymounted "on the holder 3! and precisely adjustedgauge corresponding-- relative theretoto =amaster to :theshape'ofthefollower I 0 I A: hydraulically operated lifting mechanism-- is;

provided for causinga vertical movement of' the sleeve'35' relative to the longitudinallymovable slide: 26' to "true a side face-on the-grindingwheel Ill. This-mechanism may comprisea; slide bar I05, which is slidably supported on the longitudinally movable slide 263 A follower I is fixedly mounted on the sleeve 35 and is arranged to :be actuated' byrthe' slidebar I to causeavertical movement of the: sleeved-l5; the spindle36 a-nd the truing; tools38 when theslide bar I05iis movedlongitudinally relative: totheslide- 26:

Thebar I05 iszarrangedto be traversed longitudinally relative; to the slide 26.rby. a-.hydraulically operated mechanism comprising; a cylinder I;I.II:;

which is fixedly mounted; on the. longitudinally. movable slide 26: slidably mounted piston, ILI which is-connectedto one end of a piston rod II2. 'I'heotherendof thepiston rod I12,isvconnected tothe slide-bar When fluid, under pressure; admitted:

I05. througha pipe II 3,- into a; cylinder chamber I;I4,

thepiston I I I together withthe pistonrod I12 and" The cylinder H0 ontains a,

; position, The pilot valve I20 serves to, control the.

admission to; and exhaust of fluid'from-a pair-got: end chambers I22 andil 23 formed in theopposite; ends. of theuvalve II9 to .controlythe longitu inah shifting-movementof slidablv mounted 'valve; member I24.. In theposition of the valve; I; (Fig; 5) fluid underpressure passesfromthe; valve I I9 throughthe pipe 6' into the.--,cylinder chamber I I5. Similarly fluidwithin the-cylinder,- chamber; II I may exhaustthrough the pipe I I391 through acentralpassage I 25 in the valve meme.

ber I24 andpass outwardly through anexhaust; pipe I26.;and through a throttle valve I21.into. a reservoir I32. The, throttle valve I21 1 serves to determine the rate of movement of thepistonj I I 5 and the slide. bar I I15 in either direction.

A hydraulic system isprovided:for-supplyin fluid under pressure for-actuating the. valve. parts; of: the truing apparatus comprising a: motor driven fluid pump I-which drawsafluid-throughi a pipe I3I from the reservoir I32zand forces fluid-2 under pressure-through a pipe; I33. A pressure, relief valve I34. is, connected in the pipeline. I3 1; byvmeans of which excess fluid under pressure, may be exhausted-through a pipe, I 35 directly into thereservoir I32;

A fluid-operated control valve I-=is provided for controlling the admission .of fluid tothe -c0ntrol valve H9 a This valve-is apiston type. valve comprising a slidab-ly mounted valvememben I46 which is movedenclwise by the admission'to-and exhaust-of fluid fromapair of end chambers I41:

and I48 formed at'theopposite ends; ofthe valve I 45: The valve I45- includes a pilot valve I49 solenoid1S3 isprovided or shifting-the pilot valve toward the left to facilitate reversing thepositionof the slidabl mounted valve member- I45; In the position' of the valve- I45 (Fig 5)- fluid under pressure passingthrough the pipe I33 may pass into a valve chamber I5I When; the solenoid S3 is energized the slidably mountedvalve member is toward the right-hand; end position which serves to shift the valve chamber I5I; toward'the right so that fluid under pressure passing through the pipe I 3'3: passes through the valve chamber I 51 and through a pipe I52 into the control valve II 9;

A hydraulically operated control valve I55; isprovided for controlling the admission toand ex austq fluid fromthe v i der. his alve comprises a slidablv mountedvalve member I56 wniehi l mo ed ndw se y. m an fluid n er pressure. admitted to and exhausted from a pair of end cham ers :51 and. .8.. 01rmed. at. oppo ite I58. A solenoid SI is provided which when energized shifts the pilot valve I51 toward the left thereby shifting the slidably mounted valve member toward the right. In the position of the valve I55 (Fig. fluid under pressure in the pipe I33 passes through a valve chamber I6I and through the pipe 34' into the cylinder chamber 33 to cause the piston 28 to move toward the left. During movement of the piston 28 toward the left, fluid within the cylinder chamber 32 may exhaust through the pipe 3I into a valve chamber I62, through a central passage I63 within the valve member I56, through a valve chamber I64 and exhaust through a pipe I65 into the reservoir I32. In order to facilitate controlling the rate of movement of the piston 28, a throttle valve I66 is provided in the exhaust pipe I65 so that the rate of exhaust of fluid from the cylinder 32 may be readily varied as desired to control the rate of traversing movement of the slide 26 and the truing tools 38.

' It is desirable to provide means for by-passing fluid around the throttle valve I66 so that the slide 26 may be moved rapidly in a. longitudinal direction during idle portions of its stroke. This mechanism may comprise a bypass valve I61 which is preferably a piston type valve comprising a valve stem I68 having a pair of spaced valve pistons I68 and I10 formed integrally therewith. A compression spring I1I serves normally to urge the valve stem I68 downwardly into the path of a pair of spaced adjustable dogs I12 and I13 which are carried by a T-slot I14 formed on the upper surface of the longitudinally movable slide 26. A pair of fluid pipes I15 and I11 are connected to opposite sides of the valve I61 and in the position illustrated in Fig. 5 allow fluid to bypass through a valve chamber I16 formed between the valve pistons I69 and I10 so that unrestricted flow of fluid may bypass the throttle valve I66 thereby facilitating a rapid movement of the slide 26. It will be readily apparent from the foregoing disclosure that when the valve stem I66 rides down the slope of the dog I13, the compression spring "I will cause a downward movement thereof so that the valve piston I69 cuts off the passage of fluid between the pipes I15 and I11 thus rendering the bypass valve inoperative so that the throttle valve I66 thereafter controls the rate of longitudinal movement of the slide 26.

A suitable eelctrical control apparatus is provided for controlling the energization of the solenoids SI, S2 and S3 so as to control the admission to and exhaust of fluid from the cylinders 21 and H0. As illustrated in Fig. 5, a slide bar I80 is slidablysupported on the longitudinally movable slide 26. The slide bar I80 is held in frictional engagement with the slide 26 by means of a pressure plate I8I (Fig. 3). A pair of opposed adjusting screws I82 and I83 are carried by the slide bar I80 and serve to limit the endwise movement of the slide bar I80 relative to the slide base I3. As illustrated in Fig. 5 the adjusting screws I82 and I83 are adjusted so that the bar I80 is held against longitudinal movement on the slide base I3. The slide 26 is provided with a downwardly projecting bracket I84 (Fig. 5) which serves as a support for a limit switch LSI. The limit switch LSI is provided with an actuating roller I85 which rides upon the under surface of the slide bar I80 (Fig. 5). The slide bar I80 is provided with a notched portion which is arranged so that when the roller I85 moves longitudinally the roller I85 may drop into the notched portion I86 thereby closing the limit switch LSI to energize the solenoid s3.

A main control switch I30 is provided for connecting a source of electrical energy to the circuit. A manually operable push-button starter switch I9I is provided for starting the truing cycle. The closing of the starter switch I8I serves to energize a magnetic starter switch I62 and thereby close a normally open contactor I83.

As shown in Fig. 8, if desired the truing tool holder 31 may be provided with adjustably mounted diamonds 38, 38a and 36b. The dia-- monds are mounted in adjustably mounted nibs I85, I95a and I95b respectively. The nibs are held in adjusted position on the holder 31 by set screws I96, I96a and I86b respectively. In order to facilitate adjustment of the diamonds, the truing tool holder 31 is remived from the spindle 36 and is mounted in a fixture, not shown, having a gauge I91 which is provided with a shaped surface corresponding with the shape of the follower ml. The nibs I95, I850. and I95b may then be adjusted relative to the holder 31 after which the set screws I96, I86a. and I861; are tightened to clamp the nibs I95, IBM and I95b in adjusted posiiton after which the truing tool holder 31 may again be mounted in position on the spindle 36.

The operation of the improved truing mechanism will be readily apparent from the foregoing disclosure. The main switch I00 is closed to render the electrical circuits operative. When it is desired to start a truing cycle, the push-button starter switch I8I is closed to energize the magnetic starter switch I92 and to thereby close the contactor I93. Closing of the starter switch I6I serves to energize the solenoids SI and S2 which remain energized during the traversing movement of the truing tools 38 toward the right. Energizing the solenoid SI shifts the valve member I56 into a right-hand end position so that fluid under pressure from the pump I30 passing through the pipe I33 passes through the valve chamber I6I, through the pipe 3I into the cylinder chamber 32 to cause the piston 28 to move toward the right. During this movement, fluid within the cylinder chamber 33 may exhaust through the pipe 33, through the valve chamber I64 and out through the exhaust pipe I65 and throttle valve I66 into the reservoir I32. The throttle valve I66 is set to control the normal rate of exhaust so as to control the speed of movement of the truing relative to the grinding wheel I0. In the starting position, the bypass valve I61 is open so that fluid may freely bypass the throttle valve I66 so that the initial movement of the piston 28 and the longitudinally movable slide 26 is rapid. The rapid movement thereof continues until the valve stem I68 rides down the inclined surface of the dog I13 so that the piston I69 cuts off the passage of fluid between the pipes I15 and I11 thereby slowing down the traversing movement of the piston 28 and slide 26 to a rate controlled by the throttle valve I66. The apex or corner "Nb of the follower IIII moves into operative engagement with the side face a of the forming bar 85. Engagement of the follower IOI with the surface a stops the longitudinal movement of the slide 26. The pressure however remains within the cylinder 32 so that the follower IIII is held against the surface 950 with a predetermined pressure.

During this movement of the slide 26 toward the right, the actuating roller I85 of the limit switch LSI drops into the notched portion I86 of the bar I80 to close the limit switch LSI when the apex Nb of the follower II'II moves into aaeeasae :engagement: with .the: surface :95a. in this :.position :of the tfollowerlithe truing tool ..or rdiamond .3 8b .1 has smoved K into operative eengagement with the left-hand sideiacezof the grindingwheel It. .The closing of: theilimitsswitchLsl .servesito energizethezsolenoid S3 c'which shifts :the slidably mounted valvememben I 46 toward theright: .tEig. Lin which position fluid .under @pressure may passzfroml the-:zpipe I533 throughthe valve-.chamzber 'I5I throughithei piper I52 intoathe valve-I r9. .fIhe solenoid :82 being energized, :theslidably mounted valve. member I 24. is in :aright-handtend aposition;soxthatfiuid passes through thepipe- I I3 into. the. cylinder-chamben I I4: tomove the piston #I II and the :slide bar I05 toward .the .right. .Movement of 1' the: slide -..bar I05 toward the. right .-serves.-to .raise the. follower; I06; thereby, traversing the: truing tool- 38b upwardly. acrossa .portionbf ,the side face of. the grinding wheel I B. The piston I I I rcompletes. its: movement toward the. right so that the follower rlillimides downtheleftehand slope -:on the bar I05. .When .the piston -.III reaches the right-hand end of its stroke, the. followerlfiii-rests on surface I651) of the slide-.bar 105.50 that the parts are:in.;position-for..the returnestrokeofthe slide .26. The vertical-.move- .ment of the diamond aiibcontinuesuntil the apex orrightrhand corner I IlIbof the follower IBI rides .arounde-a. portion of the radius-65b of the. forming bar 95and the truing toolfisb movesto a .correspondingposition .around the fillet Iila of .the grinding-wheel I0. During this movement .thelfillet 952) on the forming .barservesto generate a portion of .the fillet= 3a .on the left-hand .corner of. the grinding .wheeli Ill. As'soon as the right-hand corner IIiIbof the follower I6 I. reaches the pointof tangency after generating approximately -one-half of the fillet Ina on. the corner of the. wheel ID, the. pressure within. the cylinder chamber 32 causes a movement of the piston.28 toward the right so that the sloping surface IUIc ..of the follower. IBI rides upwardly until the apex .orthepoint I Illa of the. followerv IDI movesinto engagement with the'filletatwhichv position the diamond or truing toolii38a movesinto position 0 complete truing the radius or fillet Illa onv the left-hand cornerof the wheel where thediamond 38bleft ofi. .The continued movementhof the piston causesl'the apex or pointIDIa of; the follower I0 I' to ride across the horizontal face-95c on the"forming bar 95. to control the truingmovement of the truing 1:001 38a togenerate a true cylindrical peripheral surface .on i the. grinding wheel I0.

When the apex or point 'IOI reaches the'fillet 95d at theright-hand corner of the" formedportion. on the'barl 95, thediamond 38a'due'to'the action of thefollower IOI starts generation of a portion .of ajfillet or radiusIUb on the right-handcorner of the.;grinding wheel H). The piston28 continues to move toward the rightand the surface I 0 Id of. the. follower I DI 'slides'down the fillet'95don the forming. bar. 95 in a tangential path until-the apex. or. corner 'IOIe of the follower IOI moves into. engagement 'with: the fillet 95d. In this position of the parts, the diamond38 moves into engagement with-the right-hand corner of the g'rindingwheel III-to takeover where the. diamond 38a leftoff. -,During continued movement of. thepiston 28 toward the right at a slow rateofspeed, the follower. rides around the "fillet'95d and down the right-hand side'face of: the forming bar 95 so that the diamond 38 completes the generation of the fillet or radiusIIlb .at theright-hand-corner of the Na of the follower and S2.

.tion of the fillet .zgrmdinguwheelsfll and truessthe rightehand side face thereof.

\Whenthe.:.diamon1d .38: reaches this pos1t1on,..the

pipes Z I IBvand I l! .therebyspeedingaup. the longitudinal'movement..-cf the slideZt; toward the-right for s the remainder-of its stroke. During the movement of. the; slide 26 to the. extreme.- ri hthand: endof its traveL-thexroller IBE-rides out of engagement w-ithithe notch I86 .on the-:bar:I-80

thereby opening the limitpswitch LSI todeener- :gize the solenoid S3 thereby cutting 01f zfiuid under-pressure: fronm-the pipe I52. .In this position, .the;ro1ler l85. is imposition; for the return .traversingfstroke of-the-slide26 toward the; left.

When-the; slide ,2 6. reaches the right-hand-end of its-stroke a projection .200 on the slide.-26-.engages. the actuating; plunger-.20 I of. a limit switch LS2 to open the same. Opening of'the. limit switch LS2 ,serves to breakthe holdingcircuit thereby deenergizing the coilof the magnetic switch I92 thereby deenergizing the solenoids-SI The .deenergizing of solenoids SI .and S2 continues during the entire traversing movement of vtheslideZIi toward the. left. As soon-as the solenoid SI has beendeenergizedfiuid from the pipe I33 passes through the valve chamber. I6], through-the pipe 34 into: the cylinder chamber 33.toistart movement of the piston ZBtoWard the left. .The, sequenceof operationon the. return strokeis identical .-with. that just .describedin oonnectionwiththe movement ofthe pistonttoward the right. {The truing tool Bil-moves into operative. engagement with the r'ght-hand side face of the wheel IIl after which a vertical, motion of the spind1e-.36 causes the truing tool-:38 to true the side facejthereof and to true a por- IIlb at the right-hand 'corner thereof. After. this takes place, the. diamond. or truing tool 38a movesinto .positionto continue thetrl ing Operation around the remainder of the fillet What the right-hand corner-and across. the

peripheral faceof. the grinding wheel-I0. ,The

truingtool 38a trues a, portion ,ofthe fillet-10a .at. the. left-hand corner of. the grinding wheel.- to

.after..which the. diamond 38b takesv over and completes the truing of the fillet Illa at the left-hand corner. of the wheel --I 0 J and trues the left-hand .side facethereof.

'.It will thus beseen that therehasbeen'provided by this invention-2a, grinding wheel: truing apparatus-in which the various objects hereinabove .set forth together-withmany: thoroughly practical advantages .are successfully .achieved.

ing tools, aforming bar fixedly :mounted relative the base, a followerron said carrier havinga plurality aof .:apexes for engagement with the forming bar, said truing tools being shaped and positioned to correspond with said apexes, actuating mechanism on said slide operatively connected between the slide and carrier to move the carrier transversely relative to the slide, said longitudinal movement of the slide serving to position one of the apexes of the follower in engagement with the forming bar, and means actuated by and in timed relation with the longitudinal movement of the slide to initiate a transverse movement of the carrier to traverse one of the truing tools across a portion of the operative face of the grinding wheel, said longitudinal traversing means serving to move the slide longitudinally thereafter so that the follower moves along th forming bar to move another apex of the follower into engagement with the formin bar thereby moving another truing tool into operative engagement with the grinding wheel to true another portion of the operative face thereof.

2. In a grinding wheel truing apparatus for a grinding machine having a rotatable grinding wheel including a base, a longitudinally reciprocable slide thereon, means including a cylinder containing a slidable piston one of which is connected to the base and the other to the slide to traverse said slide longitudinally, a transversely movable truing tool carrier on said slide, a truing tool holder thereon having a plurality of spaced truing tools, one of said truing tools being arranged for truing a peripheral face and a pair of spaced truing tools arranged for truing opposite side faces, a forming bar fixedly mounted relative to said base, an arrow-pointed follower on said carrier, said truing tools being shaped to correspond with the apexes of said follower, a longitudinally movable cam on said slide, means including a cylinder containing a slidable piston one of which is connected to the slide and the other to the cam to move said cam longitudinally relative to said slide to cause a transverse movement of the carrier and truing tools, control means including a control valve operatively connected with said first cylinder for controlling the longitudinal movement of said slide to position one of the apexes of the follower in engagement with the forming bar, and means actuated by and in timed relation with the longitudinal movement of the slide to initiate a transverse movement of the carrier to traverse one of the side truing tools in a transverse path and through a partial radius, said longitudinally traverse means serving to move the slide longitudinally thereafter so that the follower moves along the forming bar to move the second apex of the follower into an operative position to cause the peripheral truing tool to complete the radius and move in a longitudinal direction for a peripheral truing operation and through a partial radius, said forming bar being shaped so that the follower sliding along the surface thereof moves the third apex into operative engagement therewith to shift the third truing tool into position to complete the latter radius and to move transversely to true an opposite side face.

3. In a grinding wheel truing apparatus for a grinding machine having a rotatable grinding wheel including a base, a longitudinally reciprocable slide thereon, a cylinder containing a slidable piston operatively connected between the base and slide to traverse said slide longitudinally, a transversely movable truing tool carrier on said slide, a truing tool holder thereon having a plurality of spaced truing tools, one of said truing tools being arranged for a peripheral truing operation and two spaced truing tools being arranged for opposed side truing operations, a forming bar fixedly mounted relative to the base, an arrow-pointed follower on said carrier, said truing tools being shaped and positioned to correspond with the shape of the apexes of said follower, a longitudinally movable cam on said slide, a second follower on said carrier arranged to engage said cam, a cylinder containing a slidable piston operatively connected between the slide and cam to move said cam longitudinally relative to said slide to cause a transverse movement of the carrier and truing tools, a control valve operatively connected with said first cylinder to control the admission to and exhaust of fluid from the slide cylinder to cause the first apex on said follower to move into operative engagement with the follower, a second control valve operatively connected with said second cylinder to control the admission to and exhaust of fiuid from the cam cylinder, means actuated by and in timed relation with the longitudinal movement of the slide to actuate said second control valve so as to cause a transverse movement of the carrier so that the first apex and the first truing tool move in a transverse direction for a side truing operation and to true a partial radius thereafter, said slide piston serving thereafter to cause a longitudinal movement of the first follower relative to the forming bar to move the second apex into operative engagement therewith so that the peripheral truing tool completes the radius and trues a peripheral surface and a partial radius at the end thereof, said first follower thereafter moving relative to the forming bar to position the third apex in operative engagement therewith to move the second side truing tool into operative position to complete the latter radius and to move transversely for a side truing operation.

4. In a grinding wheel truing apparatus as claimed in claim 1, in combination with the parts and features therein specified of a cycle start switch operatively connected to said first and second control valves to actuate said first and second control valves so as to cause a longitudinal movement of the slide to move th first apex of the arrow-pointed follower into operative engagement with the forming bar to position the first truing tool in an operative position, and means including a limit switch actuated by iongitudinal movement of the slide operative connections between said limit switch and the second control valve to actuate the second control valve so as to move said cam longitudinally to impart a transverse movement to said carrier and the first truing tool to true a side face and a portion of a radius, said first piston thereafter causing a further longitudinal movement of the slide so that the follower sliding on the forming bar moves the second apex and the second truing tool into an operative position to complete the radius and to true a peripheral face and a portion of a second radius at the end thereof, said longitudinal movement of the slide thereafter causing a transverse movement of the carrier under the influence of gravity so that the follower moves the third apex and the third truing tool to an operative position to complete the second radius and to true an opposite side face.

OIVA E. HILL.

(References on following page) References Cited in the file of this patent Number UNITED STATES PATENTS Name Date Danner Oct. 11, 1938 5 Alvord Mar. 7, 1939 Alvord Sept. 8, 1939 Flanders Aug. 11, 1942 Number Number 14 Name Date Casella Dec. 23, 1947 Castelli Nov. 27, 1951 FOREIGN PATENTS Country Date Germany June 22, 1937 

